Tire pressure monitoring (TPM) sensors are used in vehicles. These sensors (disposed at the tire) measure the pressure of the tire (and potentially other parameters) and transmit this to a receiver in the vehicle. When the pressure falls below a predetermined threshold, the receiver may warn the driver.
TPM sensors typically need to be activated. This is often accomplished by a technician using an activation tool. Initiation devices in the vehicle can also be used. Low frequency (LF) commands are typically sent by these devices to the TPM sensor in order to perform the activation.
Various issues have arisen regarding the programming or activation of TPM sensors. Vehicles typically require a TPM sensor identifier (ID) with a specific configuration in order to work on that vehicle. In one specific example, the TPM sensor ID may be used to differentiate between a high-level and low-level type of vehicle or between vehicles of different vehicle manufacturers.
However, since the TPM sensors have a unique ID that is programmed into the internal electronics of the TPM sensor this prevents a multi-application TPM sensor from being used on different types of vehicles thereby requiring different types of TPM sensors.
Another limitation is that with previous multi-application TPM sensors, many different protocols are transmitted so that a sensor could be used on a wide arrange of vehicle. This presents a problem because, first, the amount of information is great and its transmission consumes much battery life, causing a shorter life of the product in the vehicle. Second, many vehicle TPM systems rely on specific timing interactions between the TPM sensor and the TPM system on the vehicle.
Another limitation is associated with locking the ID or transmission protocol to the TPM sensor. Because the locking typically occurs based upon state, there is always a chance that it will have been locked according to the wrong state and send out the wrong commands.
Some TPM sensors have the ability to be locked in a certain configuration that would transmit the appropriate tire information based on the vehicle that it is installed. These sensors may need to be reset to the default condition.
One problem with this approach is that there needs to be a procedure that could reset the sensor back to its original state that is convenient to a user but not something that could easily be done by accident. If a TPM sensor is accidentally reset to its original state, then, if not relearned properly, the TPM System may fail on the vehicle.
Locking a multi-application TPM Sensor in a particular configuration corresponding to a particular vehicle set may be necessary in some circumstances. However, there is a risk in previous approaches that the TPM sensor could be locked in the wrong configuration causing the TPM sensor to fail to work with the TPM system in the vehicle it is being used.
All of the above-mentioned problems have created some user dissatisfaction with previous approaches.
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